Real-time location (RTL) systems have become popular in recent years. Examples of RTL systems are taught in U.S. Pat. Nos. 7,522,049, 9,507,915, 9,679,171, 9,838,849 and 9,872,151.
In such prior art RTL systems, the location of an object is usually determined in one of two ways.
First, the system may have a portable device, associated with an asset to be tracked, transmit an RF or other wireless type of signal to multiple receivers. Each receiver measures the signal strength of received signal. The system then equates each received signal strength to a calibrated distance and uses triangulation of those distances to calculate a location of the portable device.
Second, systems exist in which a plurality of base stations, mounted at fixed locations in a facility, transmit base station ID information using ultrasound or infrared signaling. The base station IDs are received at portable tags attached to assets to be tracked. When the portable tag receives the base station ID, it concatenates its own portable tag ID to the base station ID and transmits both IDs to a network server. The server may then determine a location by associating the asset to which the portable tag is attached with the predetermined location of the base station associated with the transmitted base station ID.
While both types of RTL systems are sufficient to locate assets, they do not make full use of what can be done with the knowledge of the location of such assets.